Vehicle accelerators have traditionally been mechanical linkages or cables that transfer the position of the accelerator to engine throttle control. In the earliest days of motoring, engine accelerators appeared first as a hand-controlled accelerator arm positioned on the steering column beneath the steering wheel. This arrangement suited early vehicles as foot pedals and generally slower speeds made a floor-mounted foot pedal unnecessary and perhaps even inconvenient. As vehicles moved toward convention multi-speed manual transmissions, floor mounted foot pedals became the norm and have generally stayed there ever since.
The earliest floor-mounted foot pedal was a formed, spring-loaded bar that extended through the vehicle's floorboard. One end of the bar included a simple pedal and the other end of the bar was attached to the carburetor by way of two or more pivotable rods. Over time, the accelerator pedal assembly became more sophisticated, with some pedals being pivotably attached to the floor or suspended from behind the instrument panel.
A conventional known accelerator pedal is illustrated in FIGS. 1 and 2 as accelerator pedal assembly 10. The accelerator pedal assembly 10 includes an accelerator pedal 12 that is attached to a vehicle floor 14 by a pivot assembly 16 at one end. The other end of the pedal 12 includes an acceleration linkage assembly 18 that is connected to a throttle body by, for example, a cable. Depending on the preferred design, either the pivot assembly 16 or the acceleration linkage assembly 18 includes a spring which returns the accelerator pedal 12 to the neutral position, i.e., the vehicle idling position.
The stiffness of the spring in conventional accelerator pedals determines the so called “pedal feel.” Some gas pedals feel too stiff to the driver and require too much force to depress the pedal to accelerate the vehicle. Other accelerator pedals can be too light to the driver's touch, are overly-responsive, and accelerate too quickly with only even the slightest pressure. Thus the tuning of the conventional accelerator pedal spring can be problematic or perhaps impossible, even when the assembly is new. If not done right, customers can be dissatisfied. When the vehicle has been used, the situation becomes more complex as spring wear may impact the “pedal feel” in a much less predictable manner.
As in so many areas of vehicle technology there is always room for improvement related to the design of accelerator pedals for vehicles. A new approach that provides optimum and tunable gas pedal feel for vehicle acceleration that does not change characteristics over time due to wear is needed to address the problems associated with known accelerator pedal arrangements.